CA2968195C - Method for producing a complex composite part, in particular having a thermoplastic matrix, and part obtained by such a method - Google Patents

Abstract

The invention concerns a method for producing a composite part having a continuous fibrous reinforcement and a polymer matrix from a composite preform, characterised in that it comprises a step consisting of: i. depositing a defined layer (110, 120) of a thermoplastic polymer on one of the faces of the preform (100), by an additive production method.

Description

PROCESS FOR MANUFACTURING A COMPLEX COMPOSITE PART, IN PARTICULAR A THERMOPLASTIC MATRIX AND PART OBTAINED BY SUCH
PROCESS
The invention relates to a method for manufacturing a composite part complex, in particular with a thermoplastic matrix and a part obtained by such process The invention and more particularly, but not exclusively, intended At aeronautical field and the manufacture of a part with a polymer matrix reinforced by continuous fibers, the shape of which comprises more than one face, said faces being flat or curved.
Such a part is, for example, a flat or curved panel comprising ribs or stiffeners or a dihedral or trihedral part without these examples do be exhaustive or limiting.
According to the prior art, it is difficult to obtain a composite part with reinforcement fibrous continuous extending along more than two faces. An example of parts extending according to two faces is an L angle. Indeed, when there are more than two faces, it is difficult, if not impossible, to maintain the continuity of the fibers in a such configuration. Also, to obtain this result additional elements must era attached to a first preform, said elements being attached by conventional assembly techniques, such as welding or co-firing we Document EP 2 726 272 describes a method for assembling a reinforcement local by welding on a panel. This process, for its implementation, requires that the polymer constituting the matrix of the panel or the reinforcement either a polymer thermoplastic and that the polymers constituting the two matrices are weldable.
In addition, a substantial tool is necessary for its implementation.
Document EP 2 987 305 describes a method and a device for welding a stiffener on a panel. This process makes it possible to simplify the tooling, but includes the same limitations as the previous one, or requires a band thermoplastic either integrated into the layup of the panel at the level of the surfaces to be welded. others processes of the prior art implement dynamic welding, for example by induction, between the parts, and require for this purpose that a metal susceptor be integrated in one of the parts assembled at the location of the weld.

2 Document EP 2 987 305 describes a process for producing a trihedral part made of a composite material with continuous fibers and matrix thermoplastic. GOOD
that this process makes it possible to obtain a part comprising 3 faces, the continuity of said faces is not secured to each other so that an opening remains between faces, which proves to be inconvenient for certain applications of this type of part, such as by example the use described in FR 2 922 276.
It is also known from the prior art to overmold, in particular by injection, arrangements in relief on a composite part with a thermoplastic matrix.
This process is used in the automotive field or in the field of goods electronic General public. It requires the development of an injection mold and remains limited to modestly sized pieces, produced in very large series. These conditions of bet implemented are generally not suitable for the aeronautical field.
The invention aims to solve the drawbacks of the prior art and relates to this end a process for the manufacture of a composite preform with fiber reinforcement continuous and polymer matrix, which method comprises a step of depositing on moon of the faces of the preform a bounded layer of a thermoplastic polymer by a additive manufacturing process. This additive manufacturing step allows, according to mode of implementation, to particularize an area of the room in terms of property, or to constitute a functional or structural relief on said preform.
Unlike the processes of the prior art, the process which is the subject of the invention do not use no or very few specific tools and has few limitations in terms of terms of size of the preform.
The term preform is used here in a broad sense corresponding to a component composite to undergo additional operations, in particular by assembly, to form a part.
The invention is advantageously implemented according to the embodiments set out below, which are to be considered individually or according to any technically operative combination.
According to an advantageous embodiment, the polymer constituting the layer deposited in step i) comprises a dispersion of metallic particles. This mode of realization makes it possible to confer electrical conduction properties or magnetic permeability at the surface of the preform in order to constitute, for example, a

3 protection of the room against lightning.
Advantageously, the method that is the subject of the invention comprises, after step i) ,a step consisting of:
make an assembly by a weld melting the layer of thermoplastic polymer deposited during step i).
This embodiment is particularly advantageous when the preform composite comprises a matrix made of a thermosetting polymer, and makes it possible to easily and locally add a layer of weldable polymer.
Advantageously, the layer deposited in step i) comprises particles metals and the welding process is a dynamic process. Such a process using, for example, induction heating or micro-heating.
waves allows the material to be heated locally, taking advantage of the susceptor effect created by particles included in the polymer layer and thus to accelerate the speeds of welding and to simplify the tools.
According to one embodiment, the layer deposited in step i) constitutes a rib extending perpendicular to the face of the preform. The term rib is here used in a broad sense regardless of any particular technical effect and means a relief of any contour protruding from the surface of the piece.
According to a variant of this embodiment, the composite preform comprises two intersecting faces and the rib extends between said two faces.
According to a particular embodiment, the method which is the subject of the invention understand after step i) a step consisting in:
make an assembly using the rib as a means of relative positioning of the assembled preforms.
This embodiment makes it possible to facilitate subsequent assembly work And particularly in the context of a so-called mechanical assembly, that is to say without against drilling, equipment such as system installation hooks, on of the aircraft structural parts. The use of additive manufacturing for realization of said ribs makes it possible to take advantage of the possibilities of the numerical control For precisely adapt the positioning of said ribs to the actual shape of there preform.
According to another mode of implementation, the composite preform comprises 3 faces WO 2016/11044

4 PCT/EP2015/081476 intersecting and the layer deposited in step i) extends between said 3 faces. This mode of realization makes it possible in particular to close a trihedral preform called corner of trunk obtained by the method described in EP 2 987 305 in particular for the purpose sealing.
Advantageously, the layer deposited in step i) is deposited according to a pattern repeated to cover the bounded area. Thus, the consumption of polymer deposit by additive manufacturing is reduced.
The invention is described below according to its preferred embodiments, in no way limiting, and with reference to Figures 1 to 4 in which:
- Figure 1 shows schematically, in a perspective view, two examples of implementation of the method which is the subject of the invention;
- Figure 2 illustrates in an exploded view from the left of Figure 1, A
example of assembly of preforms using manufacturing deposits additive;
- Figure 3 shows schematically and in a perspective view A
example of implementation of the method that is the subject of the invention on a preform dihedral;
- And Figure 4, schematically illustrates in a perspective view and in exploded view, an example of implementation of the method that is the subject of the invention on a trihedral preform.
Figure 1, according to an exemplary schematic embodiment, the method object of the invention comprises the production of an assembly zone (110) on a preform (100) consolidated Said zone (110) comprises a layer consisting of a polymer thermoplastic. According to this embodiment, the polymer is deposited on there preform (100) in the form of lines (111, 112) thus describing a pattern repetitive.
Said lines (111, 112) are deposited on the preform (100) by a process of additive manufacturing, for example a process of spraying and fusing a powder thermoplastic by a nozzle whose movements are controlled by a digital control. Such a method makes it possible to deposit lines (111, 112) of low thickness, the technological minimum being commonly between 0.05 mm and 0.1mm. According to an exemplary embodiment, the preform (100) consists of one lamination of continuous fiber fibrous plies in a polymer matrix thermosetting, for example, carbon fibers in an epoxy resin.
THE
deposition of thermoplastic lines (111, 112) makes it possible, for example, to spare a welding area.
Figure 2, the deposition of a thermoplastic film in an assembly zone (110), thus makes it possible to assemble on the surface of the preform (100) a second preform (201) made of a laminated composite material. According to an example of realization,

5 said second preform also comprises an area (210) on which a movie thermoplastic is deposited by additive manufacturing. Thus, it is possible to solder two preforms (100, 201) whose matrix polymer is a resin thermosetting. The deposited thermoplastic polymer is chosen to have a melting temperature such as the temperature reached during soldering does not affect the properties of the thermosetting matrix. Alternatively, the polymer component the matrix of one or both preforms is a polymer thermoplastic.
In this case, the deposited polymer is for example of the same nature as the polymer constituting the matrix, or is deliberately chosen for its temperature of merger inferior to the polymer constituting the matrix, or for its properties of miscibility with said polymer constituting the matrix, depending on the desired result.
According to one embodiment, the weld is made statically by pressing the second (201) preform onto the first (100) and carrying the whole to the melting temperature of the polymer at the interface of the two parts, by example in oven.
According to another embodiment, the weld is made in such a way dynamic for example by ultrasound. According to other examples of dynamic welding, this this is performed by induction or microwave. In this case, the deposited polymer is advantageously charged with particles capable of concentrating the electric field and to act as a susceptor. By way of example, said particles are particles metallic or ceramics, for example ferrites.
Returning to Figure 1, according to another embodiment of the method object of the invention, a form (120) in relief is deposited on the surface of the piece.
Figure 2, by way of example, the relief (120) is used as a means of positioning, on the preform (100) of a part (202) assembled therewith this. There part (202) thus added, is assembled by welding by gluing or by bindings. It is made of a plastic material, a composite or metal. So, the preform (100) comprises several prepositioning reliefs. As for example the

6 preform is a frame of an aircraft fuselage and the relief (120) allows the positioning a support for a system. Thus, the part (202) added East perfectly positioned on the preform.
Returning to Figure 1, the use of additive manufacturing for the realization positioning relief (120) makes it possible to combine in the same operation, that is say without dismantling the preform (100) of the machine, the production of the relief and the creation of a hole (121) perfectly positioned with respect to said relief, and so to allow the realization of a mechanical assembly of the added part positioned on this relief.
Figure 3, according to another mode of implementation of the method object of invention, the composite preform (300) has two faces, and the manufacturing method additive makes it possible to deposit a relief (320), for example a rib extending between both faces of the preform. Said rib (320) is intended for structural or functional.
Figure 4, according to another mode of implementation of the method object of invention, the preform (400) is a trihedral composite part obtained by bending according to two lines secant bends. The use of the additive manufacturing process makes it possible to report a part (420), extending over the 3 faces of the preform, for closing of said trihedral preform The description above and the examples of embodiment show that the invention achieves the targeted objectives, in particular it makes it possible to position precisely an addition of material on a composite preform, and in the same operation to produce of the additional machining, thus perfectly positioned in relation to the preform and to said additions of material.

Claims (3)

7 1. Method for manufacturing a composite part comprising a reinforcement continuous fiber and a polymer matrix from a first preform composite consolidated comprising a thermosetting polymer matrix, and comprising of the steps consisting of:
- create an assembly area by depositing on one side of the first preforms a bounded layer of a thermoplastic polymer comprising a dispersion of metallic particles, adapted to create an effect of susceptor when they are subjected to heating chosen from microwaves and induction, in the form of lines with a thickness between 0.05 and 0.1 mm following A
repeating pattern, by an additive manufacturing process; And - assembling a second preform made of a composite material laminate comprising a polymer matrix on said face of the first preform consolidated by making an assembly by fusion welding the lines of the bounded layer using a dynamic heating process selected from THE
microwaves and induction. 2. Process according to claim 1, in which the polymer constituting the matrix of the second preform is a thermosetting polymer. 3. Process according to claim 1, in which the polymer constituting the matrix of the second preform is a thermoplastic polymer.
Date Received/Date Received 2022-06-21